Recently, image forming apparatus such as copiers, facsimiles and printers, image forming apparatus using an image reading device such as scanners, and electronic apparatus such as computers and home electric appliances are downsized, and boards therein are typically connected with each other using a flexible flat cable (FFC). Since FFCs are thin and have good flexibility, FFCs greatly contribute to downsizing of such apparatuses.
Particularly, in electrophotographic image forming apparatus, a light emitting diode (LED) array head, in which plural LED arrays each including a line of LEDs are arranged in the main scanning direction, is typically used as a light source of the image forming apparatus. In this regard, a control board of the image forming apparatus is typically connected with each LED array head using a FFC. Therefore, the number of the FFCs is equal to the number of the LED array heads. Since the LED array heads are arranged in parallel in the main scanning direction and the costs of the FFC increases as the number of folded portions of the FFC increases, it is preferable to arrange the FFCs in an efficient manner in order to downsize the apparatus while reducing costs thereof. In attempting to arrange the FFCs in an efficient manner, JP-2010-217381-A discloses a technique in that FFCs are arranged while overlaid until the FFCs reach positions at which the FFCs are connected to the corresponding LED array heads.
Recently, there is a need for high-speed and high-definition electric apparatus such as image forming apparatus. Specifically, there is a need for an image forming apparatus which can form high definition images at a high speed while having a high image reading speed and a high image processing speed. In such image forming apparatus, as the image forming speed increases, the data transmission speed also increases.
However, the above-mentioned technique has a drawback in that since FFCs are arranged while overlaid, a cross talk problem is caused when data transmission is performed, and thereby data are mistakenly transmitted.
Specifically, the thus arranged FFCs while overlaid causes the cross talk problem. The cross talk problem is such that whenever a signal is sent (driven) through a wire in a FFC, a magnet field is generated around the wire. In this regard, when another wire is arranged close by the wire, the magnetic fields generated by the two wires interact with each other, and cross join of energy occurs between the signals flowing through the two wires.
When such a cross talk problem is caused, the signals flowing the FFC are adversely affected thereby, and it becomes difficult to perform accurate data transmission.
Particularly, in an electrophotographic image forming apparatus, in which LED array heads are connected with a control board using FFCs, a memory storing correction data, which are used for correcting variations of LEDs, is typically provided in an irradiating head including the LED array heads. When the control board sends a lighting signal to a LED, the control board also transmits the correction data at the same time before printing. In this regard, if the correction data are not accurately transmitted, variations among the LEDs cannot be corrected, thereby causing a problem in that an abnormal image such as vertical strip-shaped images is formed in an image.